Sudden death in an Emery-Dreifuss muscular dystrophy patient with an implantable defibrillator

We report the first case of witnessed sudden death of an Emery-Dreifuss muscular dystrophy (EDMD) patient with a properly functioning implantable cardioverter-defibrillator (ICD). This 38-yr-old woman with normal left ventricular function had a history of recurrent syncope and nonsustained ventricular tachycardia, for which a single-chamber ventricular ICD was implanted. She later collapsed suddenly and unexpectedly while at home, with witnesses present, and was found cyanotic with pulseless electrical activity by the emergency squad. This event took place in the setting of previously documented hypercapnic ventilatory insufficiency, for which she had refused the use of respiratory muscle aids to normalize alveolar ventilation. Subsequent interrogation of the ICD demonstrated normal function, with no evidence of ventricular tachycardia or ventricular fibrillation. In the hospital, her myocardial function was found to be normal by echocardiography. Further workup revealed that the patient had severe anoxic encephalopathy. She was eventually made "do not resuscitate," and she died on the sixth day of hospitalization. An autopsy was performed, and no obvious cause for the sudden death could be established. Review of the clinical presentation, with all the data available, suggests acute respiratory failure as the likely primary cause of this patient's sudden death, which then secondarily led to the observed pulseless electrical activity of the heart. The use of respiratory muscle aids--in particular, noninvasive mechanical ventilation to prevent chronic hypercapnia and cor pulmonale--is crucial for EDMD patients with symptomatic ventilatory insufficiency, for whom sudden deaths may not necessarily be of primarily cardiac origin.